Subsurface Zone in Pure Magnesium Studied by Positron Lifetime Spectroscopy

This paper presents the results of investigation of a subsurface zone created during dry sliding in pure magnesium. Positron annihilation and microhardness techniques were used to detect the defect distribution below the worn surface. Near to the surface there was found a strong gradient of dislocations and defects associated with them, which were extended more than a hundred of micrometers. The decrease of microhardness at a depth less than 30 μm from a worn surface suggested that dynamic recovery took place in pure magnesium. The defect profiles were also studied for samples exposed to compression and blasting.